The present invention relates to a probe card for semiconductors, particularly to a probe card with modular assembly configuration.
A conventional test apparatus for the semiconductor wafers comprises a probe card setup in a test head of a tester. The probe card has numerous probe needles in contact with the bonding pads or bumps on a wafer to provide electrical connection for wafer-level testing.
U.S. Pat. No. 6,344,752 entitled xe2x80x9cCONTACTOR AND PRODUCTION METHOD FOR CONTRACTORxe2x80x9d as shown is FIG. 4, referred to a probe card performs electrical testing of a wafer. It has a plurality of first electrodes 3 arranged on a silicon substrate 2 and probe terminals 4 respectively provided on these electrodes 3. Second electrodes 5 are provided on the rear surface of the silicon substrate 2. The first electrode 3 and second electrode 5 are electrically connected to each other by a connection via 6. The second electrodes 5 on the silicon substrate 2 have elastic connection members 10 mounted on the third electrodes 11A on the printed wiring board 11. Both of the silicon substrate 2 and the wafer under test are made of silicon, therefore there is no difference in thermal expansion coefficient, and can perform electrical contact precisely. To perform this, a connection via 6 has to be manufactured and installed to connect the upper and lower surfaces of the silicon substrate 2, and thus raised the problem of a higher degree of brokenness of the connection line and broken wafers. Besides, the substance of the elastic connection members 10 connecting the silicon substrate 2 and the printed wiring board 11 has to be metal. It provides not only elastic machinery connection, but also performs as an electrical connector between the silicon substrate 2 and the printed wiring board 11. Mechanics fatigue or brokenness among any one of the elastic connection members 10 will fail the electrical connection of the probe card. Besides, the silicon substrate 2 mounted on the probe card was jointly fastened on the printed wiring board 11, and did not have the detachable virtue of modular exchange.
A main purpose of the present invention is to supply a modular probe card in utilizing of a silicon substrate modularly assembled on a main board. The silicon substrate and the multi-layer printed circuit board are electrically connected by a flexible printed wiring film and coaxial wires. It is easy to manufacture the silicon substrate and have the detachable virtue of modular exchange according to the present invention.
The second purpose of the present invention is to supply a modular probe card comprising a silicon substrate assembled on a main board with sockets installed around. A plurality of detachable coaxial wires are connected to sockets on the main board for achieving variability of connecting paths during manufacturing. Thus, the probe card assembly has the effect of adjustable amendment and is suitable for high speed testing.
In accordance with the present invention, a modular probe card comprises a modular silicon substrate with first and second surfaces, assembled on a main board. It is preferable that a plurality of connecting pads and electric circuits connecting through those connecting pads are arranged on the first surface of the silicon substrate, and a stress buffer is provided on the second surface of the silicon substrate. At least a socket is installed on the main board, and a flexible printed wiring film connects through the silicon substrate and the socket. A plurality of detachable coaxial wires are connected to the socket with the main board for achieving variability of connecting paths during manufacturing, and this is suitable for high speed testing. It is preferable that these coaxial connecting wires are in the same length to avoid signal time delay.